I got my MTA on Friday, it's a Linksys RT41P2-AT. I first attached it to one of the ports off of my switch but noticed a loud hum in the background so I connected it in front of my linux box and exposed it to the world. An unfortunate side effect was that I once again changed IP addresses so it was off to xname.org to get my DNS changes in. The hum is still there.
I decided to test the heck out of this before I callled AT&T so I checked a phone connected directly to the MTA, moved it to another location and even isolated the power supply. Still the weird hum. I made my first call to AT&T on Saturday evening but was on hold for 20 minutes before giving up. I finally found some time today and was on hold for 52 minutes before I got to support. All she really did was have me repeat the same steps. Now they tell me that they will be "grooming" my line for the next 24-hours and that she has opened a trouble ticket. I don't have any good feelings about this at all. She also said that I would have to wait until my porting was complete on the 23rd before they would know. So, basically, I will have to wait past the point of no return to decide if I like it. We will see.